Is computer's locale supported? Documentation is ambiguous.

[dave-ledsign]

In your documentation site you have written:
"The problem
The above might be all well and good if the user is sitting at home where her computer's locale settings (i.e., language and geographical region) are likely set correctly."

Is it all well and good? I want the browser to supply the locale info, not the user (they might be able to change it if it is not to their liking, but they should not have to). I need to know - does this work or not? If it works, please remove the work "might". If it does not, then some of us need to look elsewhere.